Yeast and bacteria

Yeast is an essential element of the brewing process. It converts glucose into alcohol and carbon dioxide. At the moment, there are over 1,500 known types of yeast. Incredible! The three main groups are those used in bottom fermentation (such as Pils), top fermentation (ale) and spontaneous fermentation (e.g. lambic). Which yeast to choose? Use the descriptions of the various yeast types as guidance.